Customized compare

struct comp {
    bool operator() (const std::string& a, const std::string& b) const{
        if(a.size() == b.size()) {
            return a<b;
        }
        return a.size() > b.size();
    }
};
set<string, comp> st;

///////
sort(people.begin(), people.end(),
    [&](pair<int, int> a, pair<int, int> b){
        if(a.first!=b.first)return a.first>b.first;
        else return a.second<b.second;
});
or,
auto comp = [](const pair<int, int>& p1, const pair<int, int>& p2) {
return p1.first > p2.first || (p1.first == p2.first && p1.second < p2.second);
};
sort(people.begin(), people.end(), comp);